Asked to forecast what would happen after the scheduled transfer of sovereignty to Iraqi civilians on June 30, Abizaid said "the situation will become more violent" because anti-U.S. insurgents will want to destabilize that new government before it can hold elections slated for early next year.

"Moving through the election period will be violent," Abizaid added. "It could very well be more violent than we're seeing today. It is possible that we might need more forces."

There are now 155,000 coalition troops in Iraq, including 135,000 from the United States